Mounting arrangement for a fluorescent lampholder assembly



J. M. PISTEY 3,285,560

MOUNTING ARRANGEMENT FOR A FLUORESCENT LAMPHOLDER ASSEMBLY Nov. 15, 1966 2 Sheets-Sheet 1 Original Filed April 6, 1964 l IEEiI Q, m m x 4 m i mp. w i e 9 m M h 5 0 62m o, m m%fl 11 0M 8 I 2 7 W 6 7 fig I1 r fi I! m Nov. 15, 1966 J. M. PlSTEY 3,285,560

MOUNTING ARRANGEMENT FOR A FLUORESCENT LAMPHOLDER ASSEMBLY Original Filed April 6, 1964 2 Sheets-Sheet 2 INVENTOR. Ja/m' M H'sliey BY W flttorwey United States Patent 3 285 560 MOUNTING ARRANElViENT FOR A FLUORES- CENT LAMPHOLDER ASSEMBLY John M. Pistey, Fairfield, Conn., assignor to General Electric Company, a corporation of New York Original application Apr. 6, 1964, Ser. No. 357,578.

Divided and this application Sept. 22, 1965, Ser. No.

2 Claims. (Cl. 248--342) This application is a division of my co-pending application Serial No. 357,578 filed April 6, 1964.

The present invention relates to electric lampholders, and more particularly to an improved mounting arrangement especially suitable for securing a fluorescent lampholder assembly in a lighting fixture.

My invention finds particular utility in lampholders for use with fluorescent lamps. In the past the lampholder contacts which engaged the lamp pins of the fluorescent lamps have been of predominantly two types. One type is the resiliently biased contact arm or leaf spring having angular movement. This movement might also be characterized as a hinged or flexing movement. This type of contact is exemplified by my Patent 3,060,400 which I have assigned to the same assignee as the present invention. The other type of fluorescent lampholder contact is the one employing a plunger or straight line biased contact. This type of contact generally has a coil spring which biases the contact directly against the lamp pin. My Patent 2,716,738 is an example of this type of contact. The De Reamer Patent 2,584,677 which is also assigned to the same .assignee shows some additional varieties of both types of the prior art lampholder contacts discussed above.

An object of my invention is to provide an improved mounting arrangement especially suitable for securing an electric socket, such as a lampholder assembly, in a lighting fixture.

Another object of my invention is to provide an improved yet inexpensive fluorescent lampholder assembly securing arrangement adapted for cooperative engagement with a mounting nut.

Briefly stated, in carrying out one aspect of my invention, in one form thereof, I have provided an im proved mounting arrangement for securing a lampholder assembly in a lighting fixture and I have constructed my lampholder for cooperating engagement with a mounting nut. In this regard the lampholder housing has a projecting foot section with a slot passing through it. Two transverse grooves are formed in the side walls of the slot and a recessed seat is formed at the bottom of the slot. The nut has a planar section which is seated in the recess and extends across the slot. Upstanding legs formed on the base section extend into the slot and have teeth resiliently engaged within the groove to prevent the nut from being dislodged from the seat. A threaded aperture is formed in the base section of the nut and aligned with the slot so that a bolt may be passed through the slot and threaded into the nut to secure the lampholder in a lighting fixture.

The subject matter which I regard as my invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. My invention, however, both as to organization and method of operation, together with further objects and advantages thereof, may be best understood by reference to the fol- -following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevational view showing the general arrangement of a fluorescent lamp supported between a pair of lampholders embodying my invention;

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FIG. 2 is a front elevational view of one of the lampholders of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a rear view of the lampholder with the back cover and the right hand contact removed;

FIG. 5 is an edge view of the left hand contact of FIG. 4 illustrating the degree of twist in the blade;

FIG. 6 is a perspective View of the contact blade of FIG. 5;

FIG. 7 is an edge view of the right hand contact;

FIG. 8 is a sectional view taken along line 8-8 of FIG. 4;

FIG. 9 is a rear view of the back cover of the lampholder together with the fastening clip;

FIG. 10 is a front elevational view of my lampholder mounting nut;

FIG. 11 is a side elevational view of the mounting nut of FIG. 10;

FIG. 12 is a bottom plan view of the nut member of FIG. 10;

FIG. 13 is an isometric view of the nut of FIG. 10; and

FIG. 14 is an isometric view partly in section of the lampholder of FIG. 1 showing the mounting nut of FIG. 10 engaged therewith. I

Referring now to FIGS. 5 and 6 of the drawings, I have shown therein a contact or contact connector 1 cmbodying one form of the torsion contact aspect of my invention which is disclosed and claimed in my above identified co-pending application. The torsion contact shown in FIGS. 5 and 6 is constructed for use in electric sockets for engagement with the pins 2 of a bi-pin fluorescent lamp such as the lamp 3 shown in FIG. 1. The torsion contact 1 is of a thin blade construction and has a somewhat offset contact making section 4, an inter: mediate elongated section 5, a U-shaped yoke section 6 which is the mounting section of the contact and an angularly moving pressure locking type contact section 7. The torsional section of the blade 1 includes part of the oifset contact making section 4 and the intermediate section 5. While these two sections are offset along their longitudinal edges, it may be seen that they are in alignment at one point intermediate their edges and therefore they have one common longitudinal axis. The forces from the lamp pins, as will be more fully explained hereinafter, produce a torsional efiect in the blade and this efiect is distributed from the point of actual contact down through the two sections, 4 and 5. Thus sections 4 and 5 together form a unified torsion action section or torsional contact making section 8 and the actual contact making section of the blade is that portion of the larger contact making section that is actually engaged by a lamp pin. FIG. 7 shows the right hand contact blade 9. Contact blade 9 is a mirror image of blade 1 and the parts have been numbered the same. It will be understood that the operation and construction of the blades is the same, the reason for the reversal of arrangement being that one is the left hand contact blade of a pair and the other the right hand contact blade.

The plane of the contact making section 4 can be seen in FIG. 5 to be oifset from the plane of the intermediate section 5. The number of degrees by which the contact making section 4 is offset from the plane of the intermediate section 5 depends upon a number of variable factors, including the material used in con structing the blade, the thickness and the width of the blade, the amount of resistance to torsional twist desired and the size of the mating contact, etc. Of further significance would be the degree of firmness of the engagement desired between the two mating contacts. In one application I have formed my contact blades of Phosphor-bronze with the angle of the offset in this particular application being 8".

I have found it very desirable for optimal results in most bi-pin lampholder applications to hold the range of the offset between the two sections 4 and 5 of the unified torsional contact making section between 4 and 20. I have found that with an offset of less than 4' there is a marked tendency for the torsional contact making section of the blade to have a distorted uncontrolled twist varying greatly from contact blade to contact blade in a single production of blades and even varying in an individual blade from engagement to engagement by the lamp pins during continued use. A blade may even twist in one direction one time and in the other direction the next time it is engaged. This greatly reduces the reliability and serviceability of the contact during use.

As the angle of the offset is increased, the resistance to torsional movement decreases. This is because the lamp pin force is being applied more directly into direct twisting of the contact. I have found that when the offset is increased above 20", my blades 1 and 9, which are formed for use in bi-pin lampholders, have proved less satisfactory in operation. Furthermore, there is a marked tendency for the blades to tear during manufacture if the offset is increased beyond 20.

It can be readily appreciated that in certain applications torsional action is particularly desirable. For example torsional contact action can give a rigid and firm engagement against an inserted mating contact accompanied by a very desirable wiping action. With the particular arrangement shown in the drawings this wiping action occurs as the torsion contact blade is cammed around and then allowed to partially return as the lamp pin is fully positioned in making engagement with it. In other words, the torsion contact is twisted to a greater extent during an initial stage of the insertion of a lamp pin into a lampholder than it is in its final engaged position which means the contact is twisted in one direction and then due to the torsional return action moves back along the lamp pin as some of the torsional forces are reduced. This means that the lamp pin gets more than a straight line wipe as its passes along the edge of the blade into a seated position. It has been observed that the torsional section of the contact blade does not have a perfectly pure torsion action for when the blade twists around there is usually some amount of angular bending, but the characteristic feature of the torsional sections operation is a twisting or torsion action.

Turning now to a detailed description of the means for securing the contact blades 1 and 9 in the lampholder socket housing 10, attention is directed to FIG. 4. The housing 10 is recessed, recess 11 being divided into two hollow compartments 12 and 13. The hollow chambers or recesses 12 and 13 are mirror images of one another. The housing 10, as may be seen in FIGS. 24 and 9, has a front wall 14 and a rear wall 15. The rear wall 15 includes a removable cover member 16, which is secured in position by the clip 17, the two legs of which engage in the slots 17a and 17b.

Looking again in particular at FIG. 4, the longitudinal rib 18 can be seen to divide the recess 11 into the two hollow chambers or recesses 12 and 13. This longitudinal rib 18 is formed integrally with the front wall 14. Nowlooking in particular at the hollow chamber 12, a transverse rib 19 can be seen to extend across the hollow chamber 12 between the longitudinal rib 18 and the side wall 20 of the housing. This transverse rib 19 has an upper step 21 on its upper surface extending inwardly from the side wall 20. A lower step 22 is formed on the lower surface of the transverse rib 19. The lower step 22 is centrally located and spaced from the side wall 20 and the longitudinal rib 18. The transverse rib 19 is formed integrally with the front wall and projects rearwar'dly from the front wall. Transverse rib 19 is also 4 integral with the longitudinal rib 18 and the side wall which it extends between.

A pair of aligned lower ribs 23 project inwardly from the side wall 20 and the longitudinal rib 18 respectively as shown in FIG. 4. The ribs 23 are spaced below the lower surface of the step 22 a sufiicient distance to permit the insertion of the blade thickness of the contact 9 between the two ribs and the lower step surface. An upper rib 24 projects from the longitudinal rib 18 and it is spaced above the upper surface of the step 21 a sufficient distance to enable the insertion of the blade thickness of the contact 9 therebetween. A supporting fulcrum or boss 25 projects into the hollow chamber 12 from the side wall 20 above the rib 24. It is formed integrally with the front wall 14 and the side wall 20. This fulcrum boss provides support for the contact blade, i.e., a surface against which the blades outer edge can bear as it twists, and a limited engagement point from which some angular blade motion can occur.

The ofiset positioning of the ribs as just set forth and as seen in FIG. 4 gives good spacing gaps between the ribs while maintaining their effective vertical displacement small enough to effectively entrap the thin blade 9 between them. This is a feature that greatly facilitates the ease with which the housing can be manufactured. During the manufacturing operation abrasive pellets are used to eliminate imperfect edges formed during the molding of the housing and if the spaces or gaps between the ribs are too small the pellets become trapped in the small spaces. It may also be observed, particularly in FIGS. 3 and 4, that the rearmost edges of the ribs have been beveled. This has been done to facilitate the mounting of the contact blades in the housing without necessitating an assembler having to hit the slots perfectly on center.

The contact blades 1 and 9 can be seen in FIGS. 5-7 to be mirror images formed for mating cooperation with the ribs 19 in the respective compartments 12 and 13 which are correspondingly mirror imaged. Contact 1 may be seen in FIG. 4 mounted in hol low compartment 13. The detailed features of compartment 13 have not been described, it being understood that they are the same as those in compartment 12 being mirror images thereof.

Contact blade 1 can be seen to have its mounting section 6 formed in the shape of a U-shaped yoke as previously set forth. The yoke section is designed for cooperating engagement with the transverse rib 19 and the trapping ribs 23 and 24. The yoke section has an upper leg 26 which is shown in FIG. 4 in trapped engagement between the trapping rib 24 and the upper step 21. The bight section 27 extends over' the rear surface of the transverse rib 19, and the lower leg 28 of the yoke section 6 is in trapped engagement between the lower step 22 and the pair of lower trapping ribs 23. When the rear cover 16 is secured in position by the clip member 17, it overlies the bight section 27 of the blade 1 securing the blade in the housing 10.

It may be seen that the blade 1 has notched edges at 29 and 30 so that it will clear the ribs 23, and the elongated section 5 of the blade is spaced from the inner edge of the yoke section 6 so that it will clear the rib 24. The fulcrum boss 25 engages against the outer edge of the 'blade as seen in FIG. 4 to support the blade and insure that the outer edge of the blade is supported from the side wall 20 when one of the lamp pins is inserted in the lampholder. As previously mentioned, the fulcrum boss provides a support against which the outer edge of the contact blade can bear as the blade twists and it also provides a limited engagement point from which angular motion can occur.

Looking now in particular at FIG. 8 it may be seen that the torsional contact section is positioned near the front wall of the housing 10. This has the advantage of enabling fairly short bi-pins to be properly engaged. In other words, with such an arrangement it is only necessary that the bi-pins penetrate into the housing recess a short distance. It may also be seen that the offset of the contact blades is angled toward the front wall 14 and the slot 33, see FIG. 2. This .makes it unlikely that the lamp pins will push the contact blades toward the back wall of the housing beyond the end of the lamp pins or that a blade might twist out beyond the end of a lamp pin and become disengaged from a firm edge contact with the lamp pin.

Turning now to FIG. 2 the entrance slot 33 for the lamp pins may be seen formed in the upper side wall of the housing and extending into an annular opening in the front wall 14 of the housing 10 which forms slot 34 about the two section center post 35. Looking at FIGS. 4 and 6 it can be seen that the upper portion of the inner edge of the contact making section 4 is shaped so that one of the lamp pins may ride over the arcuate surface of the center post and engage against the upper projecting edge portion 36 to cam the blade aside as it passes between the post 35 and projection 36. This pin will then seat in seating notch 37 on the inner edge of the contact making section 4. A lower projection or shoulder 38 resists the passage of this pin beyond the seating notch and the upper projection or shoulder 36 resists the pins passing back by it. Of course, this resistance is due to the resiliency of the contact blade as well as the shape of the blade edge.

The other pin of the bi-pin lamp passes through the center slot in the center post and rides up over the other arcu-ate surface of the center post engaging the lower projection 38 of the other contact blade and camming the other blade aside as it passes between the post 35 and projection 38. This other lamp pin will then seat in the seating notch 37 in the inner edge of the contact making section 4- of the other blade. The upper projection 36 resists the .passage of this other pin beyond the seating notch while the lower projection 38 resists the pins passing back by it.

Thus as may be seen from viewing FIG. 2, in operation as the pins 2 of the lamp 3 are inserted into the slot 34 through the entrance 33, the lead pin passes wholly through the center slot in the center post. As the lamp is subsequently twisted, the upper pin engages against the inner edge of the contact making portion 4 camming it aside a maximum amount at 2b. As this pin earns the torsion section 8 of the blade aside, the section in effect twists or turns around its longitudinal axis and it can be seen that this torsional displacement will be fairly substantial as compared -to the :position of the section when the pin 2 is fully seated as shown at 20. This is the operational characteristic which leads to the superior wiping action by the lamp pin offset contact making section 4.

At about the same time the other lamp pin engages against the inner edge of the lower projection 38 of the contact making portion 4 of the other contact (9 in the embodiment shown) camming it aside a maximum amount at 2d. As this pin cams the torsion section 8 of contact blade 9 aside, the blade twists or turns around its longitudinal axis and is accordingly torsionally displaced. As the pin becomes fully seated as at 2e, some of the torsional forces are reduced and the blade retains less twist than it had at 2d. Of course, as previously mentioned there is also some angular or flexing motion of each contact blade as the lamp pins are being seated. The relative moment of the torsional movement and of the angular .or flexing movement varies depending upon the relationship of many factors, such as, the angle of the offset, the material used in constructing the blade, the thickness and width of the blade, etc. The combined torsional and angular displacement of the contact blades provides the necessary blade displacements for receiving the lamp pins.

In each of the contacts the trapping of the upper leg 26 of the yoke section on the transverse rib 19 by the trapping =rib 24 (see FIG. 4) segregates the action of the torsion section 8 so that it does not effect other areas of the blade below the yoke section.

Turning now to a consideration of the lower or wire attaching section 7 of the blade, attention is directed once again to FIG. 4. Two conductor receiving passageways 39 are formed through the front wall 40 of the foot portion 41 of the housing 10 for each of the blade compartments 12 and 13 (see also FIG. 2). An unlocking slot 42 is also formed through the front wall of the foot 41 for each compartment. The angular moving section 7 (FIG. 6) is divided into two pressure locking portions 43 and 44 by the slit 45 which terminates in an aperture 46. I

The aperture 46 prevents the slit 45 from enlarging.

Each of the hinged blade portions 43 and 44 has a longitudinally extending groove 47 which terminates in the outer lower edge of the pressure locking section. Each groove 47 is deepest at its terminus at the edge of the blade. Each of the blade sections'43 and 44 is positioned across a respective one of the conductor receiving passageways 35 with the deep edge of the grooves 47 aligned with the passageway. Thus when a conductor is inserted through a passageway 39, it will engage against the front edge of the blade member 7 in one of the grooves and push the blade inwardly toward the rear wall of the housing 10 passing under the blade. The blade is resilient and presses against the conductor as it passes under the blade. If an attempt is made to extract the conductor from the passageway, the pressure locking section is tightened by the reversal of the conductors movement and the extraction of the conductor is resisted. If it is desired to extract the conductor from the lampholder, a tool (not shown) may be inserted through the unlocking slot 42 against the blade and the blade maybe pushed inwardly relieving the pressure on the conductor and allowing it to be more easily extracted from the lampholder. When it is desired to string a number of lampholders in parallel, two conductors may be attachedto a single blade to form one continuing side of the parallel circuit. It should be recalled that both of the blades 1 and 9 are the same, only mirror images, and that both of the recesses 12 and 13 are the same, only mirror images, and therefore they 'have been discussed singularly, it being understood that they have the same operable construction.

Attention is directed to the fact that all of the bends or joints between the sections of both contact blade 1 and contact blade 9 are in the same direction with the exception of the offset joint which is at an angle. This arrangement enables the joints to be across the grain in a metal blade and this makes the joints stronger. It may also be observed that the lamp pin contacting edges of the blades may be formed when the blades are punched from a metal sheet. The adaptability of these blades to being shaped by punching during manufacture rather than by forming after punching of a blank, lends itself to good tolerance control and economy.

Looking once again at FIG. 4, it may be seen that the trapping of the lower leg 28 of the yoke section between the lower step 22 and the ribs 23 effectively segregates the action of the pressure locking section 7 from any effeet on any portion of the blade above the yoke section. The ribs 23 in eiTect serve as fulcrums for the hinged action of the pressure locking contact making section 7.

Turning now to a description of the preferred embodiment of the improved yet inexpensive arrangement of the present invention or means by which my housing 10 is attached to a lighting fixture, attention is directed first to FIG. 2. A slot 48 may be seen passing through the foot section 40 and a pair of opposed grooves 49 are formed in opposed slot walls. A recessed seat 50 is formed at the bottom of the slot in the lower side wall of the foot member 41. The plane of this seat is transverse to the axis of the slot. A mounting nut 51 is formed for cooperative engagement in the slot 48.

Looking now at FIGS. 14, the nut member 51 has a planar base section 52 with an aperture 53 formed centrally therethrough and a collar extension 54 protruding from one of its faces. The aperture 53 has screw threads which are continuous with threads formed in the collar portion 54, as seen in FIG. 13. Four legs 55 project from opposed linear side edges of the base section above the face of the base section opposite the collar section 54. Two of the legs are attached to each of the opposed linear sides of the base section and spaced inwardly of the ends of the other sides as shown in FIGS. 1014. Each of the legs 55 has a tooth 56 at its outer end for engagement in one of the grooves 49. It may .be seen that the teeth on the two legs on the frontally positioned side, looking at FIG. 10, face in opposite directions. The teeth on the two legs on the opposite linear side also face in opposite directions from one another and in the same direction as the teeth on the first side.

The mounting nut is made from a resilient material and it is snapped into position by forcing it upwardly into the slot until the base portion 52 seats on the seat 50 at the entrance to the slot with the teeth 56.engaged in the grooves 49. Thus the teeth 56 and the grooves 49 serve as cooperating catch means to hold the nut in position. A screw 57 can then be inserted through a fixture panel 58 as shown in FIG. 14 and through the slot 48 for threaded receipt in the nut 51. Then the screw clamps the mounting nut, the lampholder foot and the fixture together rendering the integral catch means unnecessary except to carry and position the nut prior to its clamped engagement in the fixture. Of course, the nut could be used as a bracket with an unthreaded aperture. Then a bolt could be used on the collar side for threadably mating with the screw.

While in accordance with the patent statutes, I have described what at present is considered to be the preferred embodiment of my invention, it will be obvious to those skilled in the art that numerous changes and modifications may be made therein without departing from the invention and it is therefore aimed in the appended claims to cover all such equivalent variations as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A lampholder assembly comprising a housing having a section with a slot therethrough, a pair of catch means formed on two opposed walls of said slot, and a mounting nut having a base portion and upstanding legs, a catch means on each of said legs, said nut being mounted on said housing with said catch means on said legs engaged with said catch means in said slot and with said base portion bridging said slot, and an aperture through the bight portion of said nut whereby a bolt can be received to secure said lampholder to a lighting fixture.

2. A lampholder assembly comprising a housing having a section with a slot therethrough, a pair of grooves in two opposed slot walls, said grooves being formed transverse to the axis of said slot, a recessed seat at one entrance to said slot, said seat having a plane transverse to the axis of said slot, a mounting nut having a planar base section with an aperture formed centrally therethrough, a collar extension protruding from one face of said base section about said aperture, a continuous thread being formed through said aperture and said collar, said base section having two opposed sides, and four legs projecting above the other face of said base section, two of said legs attached at the other of said opposed sides, said legs being spaced in from the ends of said sides, a tooth at the outer end of each of said legs for engagement in one of said grooves in said slot of said housing member, the teeth on the two legs on the first said side facing in opposite directions, and the teeth on the two legs on said other side facing in opposite directions from one another but in the same directions as the teeth on the first said side, said nut being secured on said seat with said legs projecting into said slot and said teeth resiliently engaged in said grooves, whereby a screw can be inserted in said slot and threaded into said aperture to secure said lampholder to a fixture.

References Cited by the Examiner UNITED STATES PATENTS 2,465,326 3/1949 Lepore 240-51. 11 2,584,677 2/1952 De Reamer 339 2,716,738 8/1955 Pistey 339 52 3,060,400 10/1962 Pistey 33953 FOREIGN PATENTS 707,819 .4/ 1954 Great Britain.

References Cited by the Applicant UNITED STATES PATENTS 2,584,677 2/1952 De Reamer. 2,716,738 8/1955 Pistey. 3,060,400 10/ 1962 Pistey.

CLAUDE A. LE ROY, Primary Examiner. J. F. FOSS, Assistant Examiner. 

1. A LAMPHOLDER ASSEMBLY COMPRISING A HOUSING HAVING A SCREEN WITH A SLOT THERETHROUGH, A PAIR OF CATCH MEANS FORMED ON TWO OPPOSED WALLS OF SAID SLOTS, AND A MOUNTING NUT HAVING A BASE PORTION AND UPSTANDING LEGS, A CATCH MEANS ON EACH OF SAID LEGS, SAID NUT BEING MOUNTED ON SAID HOUSING WITH SAID CATCH MEANS ON SAID LEGS ENGAGED WITH SAID CATCH MEANS IN SAID SLOT AND WITH SAID BASE PORTION BRIDGING SAID SLOT, AND AN APERTURE THROUGH THE BIGHT PORTION OF SAID NUT WHEREBY A BOLT CAN BE RECEIVED TO SECURE SAID LAMPHOLDER TO A LIGHTING FIXTURE. 